1. Field of the Invention
The present invention concerns to a system for treating and disinfecting water and/or wastewater. More specifically, the present invention comprises a method and apparatus capable of disinfecting a water reservoir by generating at least one of chlorite, chlorine dioxide, and chlorate and keeping a residual of ozone in the water for a longer period of time.
2. Description of the Related Art
Water in water reservoirs such as swimming pools, aquatic mammal tank, spas, fountains, and hot tubs is constantly recirculated and fresh water is normally added only to maintain the desired volume. Although this water is usually filtered continuously to keep it free of suspended matter, it frequently contains bacteria. Treatment with one or more sanitizers to control the bacteria count is necessary.
Numerous chemical compounds have been reported for use in water reservoirs such as swimming pools, spas, aquatic mammal tank, fountains, and hot tubs. These chemicals include various quaternary ammonium salts, copper salts, and oxidants such as chlorine sources, bromine sources, ozone, or peroxy compounds such as hydrogen peroxide and potassium peroxymonosulfate. The use of combinations of such sanitizers is also known.
At the present time, the main disinfectant used in swimming pools, spas and hot tubs is chlorine in the form of hypochlorite. Chlorine is an effective bactericide, but suffers from two main disadvantages: 1) at improper pH and concentration levels, it may cause eye irritation; and 2) it has to be added at frequent intervals to maintain an effective concentration for killing bacteria along with health issues.
Ozone has also been used as a disinfectant for swimming pools, spas and hot tubs. Ozone has a short half-life and will be use within seconds/minutes.
Certain quaternary ammonium compounds have also been reported as being useful in swimming pools, spas, and hot tubs as bactericides and algaecides. Those used as bactericides and algaecides have required relatively high levels to give the rapid bacteria kill times needed for pool treatment. However, at such high concentration levels, quaternary ammonium salts in general have the potential of producing objectionable, aesthetically unpleasing turbid swimming pool water having a high total organic carbon (TOC) content. Furthermore, such high concentrations of quaternary ammonium salts may increase the likelihood of skin irritation along with chlorine.
Recent developments in the prior art include the use of chlorine dioxide for treating water and/or wastewater. The area of application ranges from the disinfection of drinking water and bathing water to treatment of service water and wastewater. In comparison with the classic oxidizing disinfectants chlorine and hypochlorite, chlorine dioxide is distinguished in use by an outstanding ecobalance. Thus, when chlorine dioxide is used, only small amounts of AOX (xe2x80x9cadsorbable organic halogen compoundsxe2x80x9d; overall parameter for all chlorine, bromine and iodine compounds which can be adsorbed to activated carbon and have very different hazard potentials) and virtually no trihalomethane (TEM, haloforms) are formed.
There are a variety of chlorine dioxide generator systems and processes available in the marketplace. Most of the large-scale generators produce chlorine dioxide by reacting a chlorate ion with hydrogen ions and an electron. This reaction can be represented by:
ClO3xe2x88x92+2H++exe2x88x92=ClO2+H2O
These generators use sodium chlorate and/or chloric acid to provide the chlorate ions. Hydrogen ions are supplied by sulphuric or hydrochloric acid. The electron can be provided by a reducing agent such as methanol, sulphur dioxide or sodium chloride.
Unfortunately, a problem exists in that these generators produce undesirable by-product salts such as sodium sulfate (xe2x80x9csalt cakexe2x80x9d), sodium bisulfate, and/or sodium chloride. As the concentration of these by-products salts rises, it begins to precipitate out of solution and must be removed.
The prior art shows another process of producing chlorine dioxide from a solution of chloric acid. Chloric acid is made by passing alkali metal chlorate through a cation exchange resin. The resulting chloric acid is reduced using hydrochloric acid in the presence of a catalyst. Sodium bisulfate and sodium sulfate are produced as by-products requiring disposal in this reaction.
The prior art shows processes that produce a chlorine dioxide of very high purity at good yields, based on the chlorite used, but it is highly restricted in its applicability and is little suited to industrial application xe2x80x9con sitexe2x80x9d, not only because of the high cost of equipment for separating the chlorine dioxide, but also because of the high explosion hazard of the gaseous chlorine dioxide.
There is thus a need for a new water reservoir disinfecting system that would reduce maintenance labor and chemical costs for maintaining ponds, fountains, hot tubs and swimming pools. Also, there is a need for a disinfectant that can be produced on site to prevent the re-growth of bacterial populations in the disinfected water.
It is believed that the present invention represents a viable alternative to the above-noted problems with existing water reservoir bactericides.
It is an object of the present invention to significantly eliminate the problems and drawbacks of the prior art, while providing comparable water disinfecting results.
It is yet another object of the present invention to provide a disinfectant agent for a water reservoir system that is capable of disinfecting utilizing either no, or a small portion of, chemicals that are utilized by existing chemical disinfecting systems.
It is yet another object of the present invention to provide such a water disinfecting system that can be used to purify water for drinking, recreational, and/or industrial use.
It is yet another object of the present invention to produce chlorine-dioxide on site.
It is yet another object of the present invention to provide a water purification system that can be easily adopted into the filter lines of existing re-circulating water systems.
It is yet another object of the present invention to provide a water purification system comprising improved mechanical filtration along with improved disinfection, so as to allow the pool owner a simpler way of maintaining their pond, pool, hot tub, or fountain and cut maintenance time by 90% or more as well as chemical costs.
These and other objects of the present invention have been accomplished by a water purification system comprising, broadly, in sequence, an ozone injector for injecting ozone into a water stream; an electrolytic chlorinator for introducing at least one of chlorite, chlorine dioxide and chlorate into said stream of water; and an ozone contact chamber (OEC system).
Alternatively, the system comprises in sequence an ozone injector for injecting ozone into a water stream; an ozone contact chamber; and an electrolytic chlorinator for introducing at least one of chlorite, chlorine dioxide and chlorate into said stream of water (OCE system).
Broadly, the ozone contact chamber includes a top end, a bottom end, an output line, and an input line.
Advantageous embodiments of both system according to the present invention include the following:
A first embodiment comprising in sequence, optionally a vortex separator for initial separation of larger solids and particulate matter; optionally a mechanical filter which may be a conventional pool filter using sand, diatomaceous earth, or paper cartridge as filtering medium; followed by OEC system or the OCE system.
A second embodiment in which the contact chamber includes a drain valve at the lower portion of the contact/dissolution chamber for cleaning the chamber.
A third embodiment in which the contact chamber includes a drain valve at the lower portion of the contact/dissolution chamber for cleaning the chamber and a second valve on the output line of the contact chamber to increase the pressure in the contact chamber and allow greater dissolution of the ozone in water.
A fourth embodiment in which the contact chamber includes a by-pass line entering the contact chamber.
A fifth embodiment in which the contact chamber includes a by-pass line for entering the contact chamber and a valve on the output line of the contact chamber to increase the pressure in the contact chamber and allow greater dissolution of the ozone in water.
A sixth embodiment comprising a second electrolysis generator and control box installed in series when the pool is in excess of 25,000 gallons.
In addition, the present invention presents a process for producing at least one of chlorite, chlorine dioxide and chorate comprising;
(a) feeding ozone and oxygen into a water stream containing chloride to produce ozonated-chloride water; and
(b) electrolyzing said ozonated-chloride water inside an electrolytic cell to produce at least one of chlorite, chlorine dioxide and chlorate.
The present invention further presents a method of producing at least one of chlorite, chlorine dioxide and chlorate on site by combining ozonation and electrolytic chlorination.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter, which form the subject of the claims of the invention.